(1) Field of the Invention
The present invention relates to a battery control apparatus that controls the charge and discharge of a battery.
(2) Description of the Related Art
For example, in a series type hybrid vehicle equipped with a generator for driving an engine and a motor for driving the vehicle, the power generation of the generator is controlled such that the state of charge (SOC) indicating the remaining capacity of a battery is maintained in a predetermined range.
In this type of vehicle, since power from the battery drives the motor, the driving performance of the vehicle depends largely on the available input-output power of the battery. There are a variety of factors that decrease the available input-output power of the battery, and in particular, as shown in a characteristic diagram of FIG. 5, a decrease in the available input-output power of the battery caused by a decrease in battery temperature has a great influence on the driving performance of the vehicle.
Therefore, to ensure desired driving performance of the vehicle, in cold climates or the like, a heater has been used to increase the battery temperature to suppress the decrease of the available input-output power of the battery.
However, this necessitates adding parts such as the heater and thus causes such problems that the cost for manufacturing the vehicle is increased and the structure of the vehicle is complicated. Further, a part of heat generated by the heater escapes to parts other than the battery, and thus, there is room for improvement in terms of the energy efficiency.